ArcGIS Toolbox functions missing all parameters?

ArcGIS Toolbox functions missing all parameters?

I recently installed ArcGIS 10.3.1 and now all the toolbox functions (that I have tried) open, but they have no parameter fields. For example, the "Add Field" tool comes up with the standard toolox dialog with the title bar, buttons at the bottom, and a functional help panel, but the rest of the dialog is entirely empty.

I've run a repair on the installation.

Has anyone else seen this? Any fixes?

Same thing after uninstalling all ArcGIS applications and reinstalling. Other details: Windows 7, 64 bit, SP1, Intel CPU

Problems with JavaScript in IE were the problem. The toolbox uses JavaScript to display the parameter prompts. We used to determine the status of JavaScript in both IE and Chrome. It was working in Chrome, but not in IE even though it was enabled in the settings. We found that our virus software had disrupted JavaScript in some registry settings, and updates to IE had not completed properly. Reinstalling IE, then restarting the virus protection restored JavaScript and the toolbox parameters.